The present invention relates to a method and a device for stripping from the concrete to which it adheres the header of a wall section cast in the ground.
The art of casting a wall in the ground is well known, and consists generally in excavating a trench, placing a header at the end of the trench, pouring concrete into the trench and stripping out the header.
In these processes the trench is generally dug under bentonitic mud. Once the trench has been dug, a header is generally immersed in the mud and placed at the end of the trench. Concrete is then poured to replace the mud, the concrete therefore coming in contact with the header. When the concrete has set, another trench is cut adjacent to the first on the other side of the header, generally using the latter to guide the drilling machine.
The problem that then arises is to remove the header. Actually, the header strongly adheres to the concrete, such that it is necessary to strip it away before removing it. This stripping is generally performed by a lateral displacement with the aid of jacks or wedges. These devices, however, have the disadvantage of being complex and tying up the worksite.
It has also been proposed in document FR-A-2613395 to coat the face of the header with a thin material that can be left in the trench and to extract the header substantially vertically, abandoning the coating material.
Although it is generally satisfactory, the latter method requires the application of very great vertical force to the header.
The present invention aims to provide a new method permitting the elimination of these problems.